Sukala said the active ingredient in many pre-workout supplements is caffeine, which shouldn't be a problem for most people.

Using a caffeine-based supplement 30 minutes before a workout can improve performance, he said, especially for exercises like cycling and running.

Caffeine is the active ingredient in many pre-workout supplements

"There is definitely evidence that caffeine whether it's in a sports drink or a cup of coffee or an isolated caffeine pill, it is a known ergogenic aid, so it does give you a little bit of a boost, particularly with aerobic style exercises," he said.

"It doesn't mean you're going to lose more fat in the grand scheme of things, but it's just that from an exercise physiologist perspective ... it does delay perceived fatigue and help you shift into a fat burning mode."

While caffeine is usually harmless, he cautions that there are risks for older people and those with high blood pressure or heart conditions.

"You can get people who outwardly look totally normal but if they take a sports drink that's loaded with caffeine and strong central nervous system stimulants their heart rate could spike and their blood pressure as well," Sukala said.

"So if they get jacked up on this stuff then there's really no telling what it could do."

Sukala said regulation of pre-workout supplements in Australia is also a problem, with little way to know if the claims made on the packets are true.

"While the TGA (Therapeutic Goods Administration) and FSANZ (Food Standards Australia and New Zealand) expect manufacturers to avoid making wild claims about their products on labels and packaging, these regulations are not heavily policed," the AIS website says in its FAQ section on sports supplements.

Consumers should keep in mind that supplements are "not regulated in the same way that food and drugs are", Sukala urged, pointing to the now banned stimulant DMAA.